import type {Entries} from 'type-fest';
interface Example {
someKey: number;
}
const manipulatesEntries = (examples: Entries<Example>) => examples.map(example => [
// Does some arbitrary processing on the key (with type information available)
example[0].toUpperCase(),
// Does some arbitrary processing on the value (with type information available)
example[1].toFixed()
]);
const example: Example = {someKey: 1};
const entries = Object.entries(example) as Entries<Example>;
const output = manipulatesEntries(entries);
// Objects
const objectExample = {a: 1};
const objectEntries: Entries<typeof objectExample> = [['a', 1]];
// Arrays
const arrayExample = ['a', 1];
const arrayEntries: Entries<typeof arrayExample> = [[0, 'a'], [1, 1]];
// Maps
const mapExample = new Map([['a', 1]]);
const mapEntries: Entries<typeof map> = [['a', 1]];
// Sets
const setExample = new Set(['a', 1]);
const setEntries: Entries<typeof setExample> = [['a', 'a'], [1, 1]];
Many collections have an
entriesmethod which returns an array of a given object's own enumerable string-keyed property [key, value] pairs. TheEntriestype will return the type of that collection's entries.For example the https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries|
Object, https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/entries|Map, https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/entries|Array, and https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/entries|Setcollections all have this method. Note thatWeakMapandWeakSetdo not have this method since their entries are not enumerable.